It's free and fairly easy.

Sign up for an account, then under "my account", go to "deposits and transfers" and you can link to your bank account. It may take a day or two to verify a small transfer of funds, like a few cents. Once that's done, you can transfer from your bank account into your tdameritrade account. I believe those funds are available instantly.

Then you can go to the "trade" tab and there are numerous ways you can actually "buy" a stock.

TDameritrade has a ton of training videos that can get you started. I use TDAmeritrades trading platform called "ThinkorSwim." I'm a novice and I figured it out pretty quick, at least as far as simply buying and selling a single stock. I have a lot to learn on how to really dive into the analytics and using the platform, but that's what the training videos are for.

Also, a ton of people on here know a lot and are always willing to help out.

If you want to get started, I'd say set up an acct., transfer $500 or $1000 into the acct, buy a couple stocks and get the feel for it, then go from there.